BOULDER, Colo. (AP) — A Colorado-based biopharmaceutical company has been penalized more than $20 million for misleading investors about the efficacy of a lung cancer drug under development before raising $300 million in a public stock offering.

The U.S. Securities and Exchange Commission brought the complaint against Clovis Oncology Inc., of Boulder, and two company executives — CEO Patrick Mahaffy and former chief financial officer Erle Mast, the Daily Camera newspaper reports .

In a complaint filed in U.S. District Court in Denver, federal regulators said Clovis Oncology reported in May 2015 that its lung cancer drug was effective in reducing the size of tumors 60 percent of the time. They did not disclose updated data that showed the efficacy was actually 42 percent before its July 2015 stock offering that raised $300 million, the SEC alleged.

Clovis Oncology stock traded as high as $116 in mid-September 2015 and collapsed to $26 a share in mid-November 2015 after Clovis disclosed the drug's actual efficacy rate was 28 percent. The company stopped developing the drug in May 2016, with the stock trading in the $12 range.

Clovis shares were trading at $32.50 on Wednesday.

The company is required to pay a $20 million penalty, Mahaffy must pay $250,000 and Mast must pay $100,000 under an agreement that settled the complaint that alleged violations of federal securities law.

The SEC also alleged Mast sold company stock at artificially inflated prices and required him to repay the proceeds, plus interest, for an additional $454,000 penalty.

A Clovis Oncology spokeswoman declined to comment. The company and its executives did not admit or deny the allegations in the settlement, the SEC said.

The SEC will distribute the nearly $21 million to investors who lost money.